The invention relates to a capture combination system for an electronic organ, and affords manual control of an internal memory for establishing desired stop combinations and for storing these combinations until such time as they are called for. Upon one read-out of the memory the stop tabs which had been stored for sequentially operated on a time division multiplex basis.
Combination systems for organs have been heretofore known, including those which utilize electronic memories and time division multiplex techniques. Typically in such systems a number of pistons and a number of stop tabs are associated with each division or keyboard of the organ and certain of the pistons (generals) are capable of reading in and recalling all the stop tabs of the organ. Pistons are generally grouped in categories according to their control capabilities. Divisional pistons, for example, are associated with a corresponding division and provide for control of only those stop tabs which are associated with that division. Divisional stop tabs are generally grouped in adjacent positions, there being one group for each division. In addition general pistons are provided for control of a combination of all the stops in the organ simultaneously, regardless of the relationship of those groups or those stops to specific divisions of the organ. It is required that the general pistons in no way restrict selection of the divisional pistons or divisional stops and vice versa.
Combination stops of the multiplexing type require a memory into which stop tab information may be stored and from which the information may be read when required. In the present case, the memory is totally internal of the organ and takes the form of a plurality of electronic shift registers. A capture and combination system permits the organist to set information into the memory by means of simply operated controls, information being constituted of those groups of stops for a division or for the entire organ which the organist has found by experience to provide pleasing combinations of tones. Absent a combination stop action the organist would be required to select the set of tabs by hand, and this is a time consuming operation, lending itself to inaccuracy because of the speed with which the selection operation must be carried out and also because great reliance must be placed upon the memory of the organist. Prior art systems have provided for multiplexing piston positions, since there may be approximately 25 such pistons in a church organ, and also provide for multiplexing the tab position information. In one system known to applicant, all the information available i.e., piston positions and stop tab positions are continuously recycled during read-out of memory. In the present invention, pistons are not multiplexed and the read-out operation is carried out only once, in the process reading into memory or out of memory required positions of all 128 tabs which are present.